php многоуровневое меню

есть цыкел с меню

[192] => Array
        (
            [id] => 192
            [parent_id] => 0
            [order] => 20
            [type] => PAGE
            [date] => 2017-10-30 05:25:15
            [date_publish] => 2017-10-30 05:25:15
            [slug] => 
            [repository_id] => 357
            [is_visible] => 1
            [is_private] => 0
            [image_filename] => 
            [id_page_lang] => 991
            [page_id] => 192
            [language_id] => 4
            [navigation_title] => level menu 1.0
            [body] => 
            [description] => 
            [keywords] => 
            [children] => Array
                (
                    [0] => Array
                        (
                            [id] => 193
                            [parent_id] => 192
                            [order] => 22
                            [type] => PAGE
                            [date] => 2017-10-30 05:25:15
                            [date_publish] => 2017-10-30 05:25:15
                            [template] => page_sale
                            [template_header] => 0
                            [template_footer] => 0
                            [slug] => 
                            [repository_id] => 358
                            [is_visible] => 1
                            [is_private] => 0
                            [image_filename] => 
                            [id_page_lang] => 1009
                            [page_id] => 193
                            [language_id] => 4
                            [navigation_title] => level menu 1.1
                            [body] => 
                            [description] => 
                            [keywords] => 
                        )
                )
        )
[193] => Array
        (
            [children] => Array
                (
                    [0] => Array
                        (
                            [id] => 194
                            [parent_id] => 193
                            [order] => 21
                            [type] => PAGE
                            [date] => 2017-10-30 05:25:15
                            [date_publish] => 2017-10-30 05:25:15
                            [template] => page_sale
                            [template_header] => 0
                            [template_footer] => 0
                            [slug] => 
                            [repository_id] => 359
                            [is_visible] => 1
                            [is_private] => 0
                            [image_filename] => 
                            [id_page_lang] => 1024
                            [page_id] => 194
                            [language_id] => 4
                            [navigation_title] => level 1.1.2
                            [body] => 
                            [description] => 
                            [keywords] => 
                        )
                )
        )

Меню с 1 по 2 уровень у меня мозгов хватило написало а как написать 3 уровень. То есть parent_id у 3 уровня это ид 2 уровня. У меня функция на вывод вот такая

   function echo_menu($menu_array) {
        foreach ($menu_array as $menu) {
            echo "<li>{$menu['navigation_title']}";
            if (isset($menu['children'])) {
                echo '<ul>';
                echo_menu($menu['children']);
                echo '</ul>';
            }
            echo '</li>';
        }
    }
    echo_menu($mainmenu);